Optimising the design of agrivoltaic systems for enhanced land productivity and electricity supply in Sub-Saharan Africa

Abstract

Agrivoltaic systems offer the potential to boost land productivity, reduce water consumption and improve access to energy: an energy-food-water nexus solution. Agrivoltaic systems are promising for regions with relatively low land productivity and both energy- and water-access challenges, such as sub-Saharan Africa. However, there is a lack of research exploring the use of agrivoltaics in such contexts. This study addresses that gap. It uses both energy-system and crop modelling to explore optimal agrivoltaic system design and deployment for a medium-sized farm, located in Zimbabwe, where electricity is expensive and unreliable. We compare conventional, ground-mounted PV mini-grid systems with three agrivoltaic system configurations. We model fixed-tilt, single-axis tracking and vertical bifacial configurations installed above wheat and maize. We calculate the optimal required system sizes at 100% and 95% reliability levels. We find that the cheapest agrivoltaic system (on a unit cost basis) is single-axis tracking, with a unit cost only 11% higher than the ground-mounted PV at an equivalent 95% reliability level. Under our base-case scenario, high electricity costs from the grid mean that the farm is operating with a deficit (when considering crop revenues). However, with agrivoltaic systems, the deficit is significantly reduced and at 95% reliability, the farm becomes profitable with crop revenue exceeding upkeep costs. Of the agrivoltaic systems, all were profitable though this varied depending on the ratio between module spacing and height (P-by-H ratio). We found greater system profitability at higher P-by-H ratios, with the largest improvement when switching from a P-by-H ratio of 2 to 3. All agrivoltaic system types can achieve land-equivalent ratios (LERs) greater than 1, depending on the P-by-H ratio, indicating improved efficiency. Our calculation of the price-performance ratio (PPR) found that all system types were economical.